#include <bits/stdc++.h>
#define sz(v) ((int)(v).size())
#define all(v) (v).begin(), (v).end()
using namespace std;
typedef long long lint;
typedef pair<lint, lint> pi;
const int mod = 1e9 + 7;
const int MAXN = 250005;
const int MAXL = 2755;
vector<lint> dist[MAXN];
vector<int> gph[MAXN];
vector<int> ngph[MAXL][MAXL];
lint eist[MAXL][MAXL];
struct node{
int x, y; lint dist;
bool mode;
bool operator<(const node &n)const{
return dist > n.dist;
}
};
void solve(int n, vector<pi> edg, vector<int> vect, int s, int e){
memset(eist, 0x3f, sizeof(eist));
int p = 0;
vector<pi> cycs;
for(int i = 0; i < sz(vect); i++){
for(int j = 0; j < vect[i]; j++){
dist[p].resize(vect[i], 1e18);
p++;
cycs.emplace_back(i, j);
}
}
while(p < n){
dist[p++].resize(1, 1e18);
cycs.emplace_back(-1, 0);
}
for(auto &[u, v] : edg){
if(cycs[u].first >= 0 && cycs[v].first >= 0){
ngph[u][cycs[v].first].push_back(v);
ngph[v][cycs[u].first].push_back(u);
}
else{
gph[u].push_back(v);
gph[v].push_back(u);
}
}
for(int i = 0; i < n; i++) sort(all(gph[i]));
priority_queue<node> pq;
auto enq = [&](int v, lint d){
if(sz(dist[v]) > 1 && d % sz(dist[v]) == cycs[v].second) return;
if(dist[v][d % sz(dist[v])] > d){
dist[v][d % sz(dist[v])] = d;
pq.push({v, (int)(d % sz(dist[v])), d, 0});
}
};
auto enq2 = [&](int x, int y, lint d){
if(eist[x][y] > d){
eist[x][y] = d;
pq.push({x, y, d, 1});
}
};
memset(eist, 0x3f, sizeof(eist));
enq(s, 0);
vector<int> visCount(n);
while(sz(pq)){
auto x = pq.top(); pq.pop();
int v = x.x;
int w = x.y;
if(x.mode == 0){
if(dist[v][w] != x.dist) continue;
enq(v, x.dist + 1);
visCount[v]++;
for(auto &y : gph[v]){
if(sz(dist[v]) > 1 && visCount[v] > 1 && sz(dist[y]) == 1) break;
enq(y, x.dist + 1);
if(sz(dist[v]) == 1 && sz(dist[y]) > 1){
enq(y, x.dist + 1 + ((cycs[y].second - x.dist) % sz(dist[y]) + sz(dist[y])) % sz(dist[y]));
}
}
if(sz(dist[v]) > 1){
int sum = 0;
for(int i = 0; i < sz(vect); i++){
for(int j = 0; j < vect[i]; j++){
lint newDist = x.dist + j * sz(dist[v]);
enq2(v, sum + newDist % vect[i], newDist);
}
sum += vect[i];
}
}
}
else{
if(eist[v][w] != x.dist) continue;
for(auto &y : ngph[v][cycs[w].first]){
if(cycs[v].first >= 0 &&
cycs[v].first == cycs[y].first &&
x.dist % sz(dist[v]) == cycs[y].second &&
(x.dist + 1) % sz(dist[v]) == cycs[v].second){
continue;
}
enq(y, x.dist + 1);
}
}
}
lint ans = *min_element(all(dist[e]));
if(ans < 1e17) cout << ans << "\n";
else cout << "impossible\n";
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n, m; cin >> n >> m;
vector<pi> edg;
for(int i = 0; i < m; i++){
int u, v; cin >> u >> v;
edg.emplace_back(u-1, v-1);
}
vector<int> idx(n, -1);
int cnt = 0;
int k; cin >> k;
vector<int> siz(k);
for(int i = 0; i < k; i++){
cin >> siz[i];
for(int j = 0; j < siz[i]; j++){
int v; cin >> v;
idx[v - 1] = cnt++;
}
}
for(int i = 0; i < n; i++){
if(idx[i] == -1) idx[i] = cnt++;
}
for(auto &[u, v] : edg){
u = idx[u];
v = idx[v];
}
solve(n, edg, siz, idx[0], idx[n - 1]);
}
